Method _fakeSetInterval

packages/jest-fake-timers/src/legacyFakeTimers.ts:542–565

(
    callback: Callback,
    intervalDelay?: number,
    ...args: Array<unknown>
  )

  }

  private _fakeSetInterval(
    callback: Callback,
    intervalDelay?: number,
    ...args: Array<unknown>
  ) {
    if (this._disposed) {
      return null;
    }

    if (intervalDelay == null) {
      intervalDelay = 0;
    }

    const uuid = this._uuidCounter++;

    this._timers.set(String(uuid), {
      callback: () => callback.apply(null, args),
      expiry: this._now + intervalDelay,
      interval: intervalDelay,
      type: 'interval',
    });

    return this._timerConfig.idToRef(uuid);
  }

  private _fakeSetTimeout(
    callback: Callback,